1. Field of the Invention
Aspects of the invention relate generally to multiple-module electronic systems, and more particularly to power control of multiple-module electronic systems.
2. Description of the Prior Art
Many electronic systems, including a variety of computing systems or platforms, employ a number of separate components or modules coupled together to operate in a cooperative manner to perform one or more tasks or functions. Further, some of these systems may form a system hierarchy, wherein a number of components may form one or more subsystems, the subsystems are grouped to form larger subsystems, and so on. In one example, a switch for a telephone system, such as a Public Switched Telephone Network (PSTN), may include one or more network elements, wherein each element includes one or more network servers, such as blade servers. Other modules, such as data storage subsystems like disk drives, may also be included in the switch. Myriad other electronic systems representing a virtually unlimited number of system configurations also exist.
Each such electronic system requires one or more electrical power supplies to allow the system to operate. Each component or module of an electronic system typically consumes electrical power at a rate determined by the electronic design of the module, the particular components employed, and other factors. Typically, the power consumption of each module is not constant, but instead changes depending on the particular functions being performed by the module. More specifically, many modules consume significantly more power for a period of time immediately after being turned on or activated. Thereafter, the power consumption typically moderates to a more-or-less constant, or “steady-state,” power level below the “start-up” power level. For example, disk drives are well-known for consuming a significant amount of power shortly after being activated so that the disks of the drive may be “spun-up” to their normal operating rotational speed. After that rotational speed is attained, the power requirements of the disk drive normally decrease. Similarly, computer processing modules may have cooling fans associated therewith which initially require more power to spin up to an operating speed. These processing units may also perform intensive testing of various components, such as memory and other peripheral integrated circuits, which may also temporarily require additional power. Many other examples also exist.
Typically, all modules of an electronic system are powered up essentially simultaneously. As a result, the system requires a relatively large amount of power initially before reducing its demands, typically over a few seconds. Accordingly, power supplies used for such systems, as well as the building or other infrastructure tasked with transferring the power from a power grid to the power supplies, are designed to provide that peak power demand during a power-up cycle. Since the instantaneous power requirements of a system typically drop significant within a few seconds or so of initial power-up, the power supply and related infrastructure typically are designed and manufactured to provide a level of power much higher than required for normal steady-state operation of the electronic system in question. Such designs often result in a waste of financial resources on power consumption requirements that the enterprise operating the system could deploy elsewhere.